Hydraulic hand



' n March 2S, 1939. G. H. HEDRICK ET A1.

HYDRAULIC4 HAND Filed June 42e, 1936 EN wam mv 1nu: fia!" Wam/.6.

AT RNEYS.

'scale-through the piston 5 Patented Mar. 2s, v1939 t zlslso PATENT.OFFICE 2,151,850 "mimmo mim Gale Il. Hedrick, Francis P, Myers, andRawson E. Stark, Pittsburgh, Pa., assignors, by mesne assignments, to I.A. Simon, Pittsburgh, Pa.-

Application June 26,

14 Claims. This invention relates to means for mechanically andautomatically controlling. the steering mechanism of road vehiclesagainst accidental and sudden displacement, -and it is among the 5objects thereof to provide such a device or simple and'inexpensiveconstruction adapted for ready attachment to the road vehicle, and whichshall be adapted to prevent sudden displacement of the vsteeringmechanism and also absorb the sud# den shock and impact to which thesteering mechanism is subjected when the wheels of the road vehicle`.pass over or strike .path of travel.

A device suitable for the purpose may be termed a hydraulic handconsisting of a cylinder containing a viscous iiuid such as oil, inwhich is disposed a leaky' piston having slots or perforations to permitthe retarded passageof fluid through the piston head. By attaching thecylinder to a proposed to employ such fluid displacing means forcontrolling the steering mechanisn oi' road-vehicles, the presentinvention isdirected to improvements, particularly in the control lofthe fluid displacement vof such devices, t

eiil'cient. morevsafe, and reliable in use. s. 'Ihe invention willbecome more apparent from -a -considerationoi the accompanying, drawingconstituting a hereof` in which like Ireference c charactersdesignatelike parts and in which:

' Fig. 1 is a N.view diagrammaticaily illustrating the arrangement of apair of vehicle'wheels, axle and steering mechanism, a'nd the eii'ectof'sudden shock or impact upon the wheels and steering device;"

Fls. 2 a bottom tie rod of' thesteering mechanism with the hydraulichand attached thereto;`

. Fig. 3 is across-sectional elevational view tak along the line'S-l,Fig. 2;

and piston element that is attached to the wheel axle and tie rod in themanner shownin Fig. 2;

Fig. 5 a crosssectional view of an' enlarged yhead'of Fig-4 takenf'onthe line 5 5, Fig. 6;

obstructions in. its

stable element ofthe vehicle,.such as the front. wheel'axle and thepiston rodjto the steering hat render such devices more plan view of awheel axle and Fig. 4 a cross-:sectional view of a fluid cylinder 193s,'serial-No. 87,5 80

ici. 28e-9o) l Fig. A6a vfront elevational view of the piston head orvalve; y Fig. 7 a top'plan view of a half section of the .,pistonhead;

' Fig. 8 a cross-section of a fragmentary portion 5 0f the head of Fig.'7 taken along-the line 8 8 thereof Fig. 9 a. top piston head;

Fig. 10 isa cross-section of a fragmentary por- 10 tion/of the head ofFig. 9ftaken along the line lli-ill thereof: and

Figure il isy anenlargedrsectional-view ofthe packing structure with theconcavity of the metal disc shown somewhat exaggerated.

4With reference to Fig. .l of the drawing, the structure thereinillustrated comprises a wheel axle I which is of--the conventionalI-beam type oi' axle for the front wheels oi' automotive vehicles; 2 thesteerlngknuckles or king pins; l the 20 vehicle wheels; l the tie rod;and 5 the tie rod Joints. The foregoing elements arev oi theconventional form. If thevehicleis travelling in the direction of thearrow'and the tire on the-right-hand side 25 'blows out or s'trikes anobstruction, the tendency is for the wheel to assume the position shownby the dotted lines. This `results from the fact that @the forwardmotion of the tire is' suddenly re' 'plan view of amodied form of carrythe axle unit forward. which causes the wheels to assume. the positionshown in Fig. l.

vConditions such as-those described are dangerous and often result inaccidents as they come without warning and give the driver little or no35 opportunity to realize what has happened. By the timethe human mindcan :react to the situation, the front' wheels have assumed the;position shown by the dotted lines in`Fig. 1, and an accident hasresulted. By attaching to the vehicle. 40 the hydraulic hand constructedin. accordance with Figs. 4 toll ofthe drawinginthemanner as shown inFig. 2 of the' drawing, the sudden swerving of the front from anycause.. whatever is eliminated an'd the shocks ordinarily 45 transmittedthroughthe steeringmeohanism toA thedriverareabsorbed.

The hydrauiichand will nowvvbe described in connectionwith '4 to 11inclusive oi' 'the drawing, in which t enumerai Sf'designates a 50 iiuidcylinder having threaded ends 1 and 8 for interacting with the threadsof caps 9 and IILthe cap l! forming Va'closureand being provided with aboss Il. having a threaded interior ilvfor receiving a threaded arm I3,2, that is pivotaltarded-and the inertia ofthe vehicle tends to Sii lyattached to the wheel axle l of the vehicle. The clamping bracket l isadjustable to adapt it to different size axles and is secured inposition by a clamping bolt I6 and the spring bolts i1.

The end cap I9 of the fluid cylinder is provided with a counter-bore l2and a central opening i9. for receiving a rod 29 of a pair of piston orvalve elements 2| and 22. The sliding joint for the rod 2l and openingI9 is packed against leakage by the employment of a wiper gland 22 and aplurality of laminated packing glands 22a which are held in place by aconcave disk 24 that seats against a shoulder 25 in the cylinder 9 asshown in Figure 11 whereby the disc 24 is movable toward the packing. Itwill be -noted that the disc. 24 forms an end wail of a working chamberin the cylinder and acts lto confine the packing. A coil spring 22 isdisposed in the counter-bore portion I2 of the end cap I9, one end ofthe spring abutting against one 22a. v

The packing gland of t e cylinder 3 is constructed of laminated membersof compressible material, e. g., synthetic rubber impregnated withgraphite, the laminations functioning to prevent scoring o f the pistonrod 29 as any particlesr attempting to pass through the packing will bedisl placed into the laminated structure, and the laminations of thepacking further function to receive oil between contiguous laminatedmembers to aid in lubricating the piston rod joint. The purpose of theconcave washer counteract the swelling', if any, 22a. 'Any swelling ofthe glands will tend to nat- `ten` washerl 24, thereby increasing thepressure against the cylinder wall, i. e. the compressible glandmaterial will spread laterally against the cylinder wall and about theperiphery of the piston rod. Conversely, the confining means for thepacking material, namely the disc 24 which is on the chamber side of thepacking, is moved when said valvefelements lock and are moved in thedirection of the packing whereby the compressible material is compressedand expanded laterally to seal the chamber. In the gland material willproduce a tight seal about the cylinder wall and the piston rod and when4 the pressure in the cham r is toward the paci:-` lng, the disc 24 willbe bodily moved to compress the packing material against the cap I2whereby it is caused to exert a similar sealing action of the chamberwall and the piston rod so 'as to prevent leakage of the hydraulicfluid. The function of the coil spring 22 is to'maintain constantpressure upon the wiper gland 22 andthe gland 22a, --thus compensatingfor wear and maintaining the'glands in proper position.`

"lhe piston or valve elements 2i and 22 areof a. construction shown vinFigs. 5 to 10 of the draw-1 ing' and are mounted on flanged quill nuts21,

which in turn interact with threads 22 .formed on the end of the pistonrod as is clearly shown in.l"ig. 5 of the The valve elements.A

and 22 have an inner-bore 29 which is a slidingV fit on the milled orcylindrical-body portions 22 of the quill nuts 21. The elements 2i and22 are also counter-bored at 2l to form a nest for a coil sprlng22.`The' overall length of the cylindrical portions 22 of the quills 21 isslightly more than the agtrl'te width or thickness 'of-valve elements 2iand 22, and the coil spring 22 separates the piston elements to providea gap 22, the size of which `is' selected in accordance withthe vis-'-cosity of the fluid in cylinder 2, and which, for

of the laminated packing glands 24 is to of the glands' other words,swelling of Pressure the valve to the other. The staggered relationshipof the cylindrical openings 34 is effective to accomplish the requiredvalve action in cutting off the flow of fluid through the piston when ashock is encountered and the discs are forced together. As shown in Fig.5, the inner ends of the perforations are ared or rounded as shown at35, to reduce the resistance to the flow through the flow passages 34.The valve elements, if desired, may be maintained relatively fixedagainst the rotation of one with respect to the other by any suitablemeans which, as explained, enables the valve elements to be free toreciprocate to -eifect the valve action.

In the modications shown in Figs. '1 to 10 inclusive, elongatedopenings, 38 or slots 31 may be employed instead of the cylindricalperforations 34 and the juxtaposed faces of the valve elements '2| and22 may be depressed or cute away as shown at 39, Fig. '1, and 39, Fig.9, leav ing the surfaces surrounding the perforations or slots :i6A and31 elevated as designated by the numerals 49 and 4l, respectively. Theends of the perforations or slots of Figs. 7 and 9 are flared as shownat 42, Fig. '1, and 42, Fig.v 9, and also as shown in Figs. 8 and 10,respectively. In these modifications when the valve elements are broughtinto abutting relation, a slight overlapping of the edge portions of theelevated surfaces 49 and 4I takes place such as will effec-4 -tively barthe passage of fluid.

Again referring to Fig. 2 of the drawing, the piston rod 29 is attachedto the tie rod 4 of a steering mechanism by means of a clamping unit liato which it is attached by a ball and socketor a universal jointassembly b.

'I'he above-described mechanism operates briefly as follows:

The' piston or `valve elements 2l and 22 are movable on the quills 21within the limits of the shouldersof ythe quills against which they abutin 4an amount equal'to the gap 22, and are normally extended by the coilspring 22. The areas of the flow passages 24, 23 and 21, Figs. 6, 'I and9, respectively, and the gap 22 are so propoi'-, tioned vthat at normalrate of movement of the steering tie rod 4 and the correspondingmovement of the valve elements 2l and 22 within the cylinder, noappreciable resistance to the passage of 'oll from one-sideof the pistontothe other ris encountered. However. a sudden' shock or imthe directionof travel, tocause it to move against theo'ther valve element, therebyclosing the gap 22;' f1he actual closing ofthe valve elements may becaused by the creation of a vacuum behind the piston upon suddenmovement. Such 'vacuum i would causeithe uld to flow from between thevalve elementsjiand permit the device to function in the manner hereindlsclosed.- The purposezoi' the invention 'is to provide means to renderthe closing of the-valve element more rapid than has beeny possible inythe past. Any force applied to the elements that will cause 'the fluidto be on-one of the elements, depending on n squeezed from between theelements will Veffect lthe purpose of the stabilizer and this force maybe considered as caused by pressure on the forward element, or by thecreation of a vacuum behind the pistonelemnt, or a combination of bothactions.) The cylindrical openings 34 in the opposed valve elements arestaggered and therefore when the gap 33 is closed no uld can flowthrough the piston element and thus further travel of the piston elementis prevented. The various forms of ow passage with their ared.inner-ends as shown in Fig. 5, and the various forms of juxtaposed facesof the piston elements, as shown in Figs. 'l and 9, are designed toprovide a better seal when the valves are closed, and to accelerate theclosing action of the piston elements 2| and 22.

The flaring of the inner ends of flow passages 34 reduces the resistanceoffered tothe flow of fluid through this portion of the ow passage. Theexternal ends of passages 34 are formed square and the fluid willencounter more resistance in flowing through the square ends of paspages34 than when flowing through the flared ends because of the greaterturbulence set up by these square edges. Thus when a shock isencountered and one of the valve elements is forced against the otherthe fluid in gap 33 will be squeezed out through the flared openingsof'passages 34 at a much greater rate than fluid will tend to enter thegap 33 through the square ends of passages 34. This effect, as will beunderstood from principles of hydraulic ow, is more pronounced as thevelocity of the flow is increased so that while the fluid can beexhausted from the gap quite4 readily through Ithe' ared open- 'ings theabilityof fluid to -enter is to a large extent prohibited by theincreased resistance of the square ends' of the vflow passages 34. Inthis manner a more instantaneous closing of the valve elements isaccomplished. While the operation of the ared openings has beendiscussed with reference to flow passages 34 it is evident that the sameresult obtains in the case of passages 36 and 31'of Figures '7 and 9respectively.

The undercutting or relieving of the juxtaposed faces .of the valves asshownv in Figures 'l to 10 inclusive serves a twofold purpose. duces theresistance offered to the flow of uid through the valve element. It is awell known principle of hydraulics that as the volume of a flow passageincreases', the `velocity of flow of a fluid through the passagedecreases. Another Aprinciple isv that as the velocity of a uid owdecreases, the resistance decreases.l Therefore as the undercutting ofthe faces enlarges the .crease in Velocity of flow through the gapfurther reduces the resistance oiieredto the ow of fluid from the gapwhen a shock is encountered. lSecond, the undercutting reduces the areaof contact between the valve elements when they are forced` against eachother under the influence of a shock. It is seen then that the entirehydrostatic pressure built up against the exposed side of a valveelement under a shock is distributed over the abutting or contactingarea of the valve elements. I'heitotal areathus in contact vbethe unitpressureon the contacting surface is much greater than on the exposedsurface.` This is a desirable result in that it provides a better sealbetween the seated valve elements.

The equal spacingof the apertures or flow pas'- First, it re'-l sagesabout the disks provideva uniform distance of oiltravel through any onepassage `from onel sistance to the flow of the oil -through theseapertures or flow passages is greatly reduced because the .distance fromone .aperture to the next is such that the oil ows a uniform distance.

Again referring to Fig. 4 of the drawing, it will be apparentthat thenormal or slow movements of the piston elements through the oil incylinder 6 in response .to normal steering action of the vehicle willproduce a minimum resistance of oilthrough the staggered apertures andthe gap 33. However when a shock is encountered that c auses a suddenacceleration in the movement of the piston through the cylinder apressure is built up on the forward side of the piston that overcomesthe force of spring 32 andthe forward valve element is forced intoabutment with theother valve element. Due to the stagpossibility of thewheels or steering mechanism being subjected toa so-called shimmey, andthe h'azards of the vehicle leaving the road when it strikes arough orsoft shoulder or other obstacle, or when the tire blows out, is entirelyprevented Thus it is seen that at normal operation, there will be noimpedance to the normal steering of J'the vehicle, but upon suddenacceleration of the tie rod, atremendous resistance is immediately setup to counteract the accelerating force.

Although several embodiments of theinvention have been hereinillustrated and described,

it will be apparent to those skilled in the art that variousmodifications may be made in the details of construction withoutdeparting from the prin.- A

ciples herein set forth.

We claim:

1. A uid ow controLmechanism comprising a stationary cylinder and amovable piston, the piston having a pair ofx valve elements cooperatingwith the walls of the cylinder to provide a substantially leak-proofiit, said elements being mounted for axial movement on thepist'on rodand being normally spaced apart to form a gap between said pair ofelements, said elements having i'low passages in angularly spacedrelation, the passages of one element being in staggered relation tothe, passages of the `other element, and'meanson the juxtaposed faces ofsaid pair-of valve elements. to minimizethe resistance to the flow ofthe fluid when said elements are being moved into contact.

2. A fluid flow control mechanism comprising a stationary cylinder and amovable piston, the piston having a lpair of Valve elements cooperatingwith the wallsof the cylinder to provide a substantially leak-proof fit,said elements `being mounted for axial movement on the piston rod andbeinggnormally spaced apart to form. a gap between said pair ofelements,'sa.id` elements, having flow passages in angularly spacedrelation,lthe passages 'of one element being in stagment, said valvedelements having raised contact surfaces around the ow passages on theirjuxtaposed faces.

3. A fluid flow control mechanism comprising a stationary cylinder and amovable piston, the piston having a pair of valve elements cooperatingwith the Walls of the cylinder to providea substantially leak-proof fit,said elements being mounted for axial movement on the piston rod andbeing normally spaced apart to form a gap between said pair of elements,said elements having flow passages in angularly spaced relation, thepassages of one element being in staggered relation to the passages ofthe other element, said valved elements having raised contact surfacesAaround the flow passages on their juxtaposed faces of such dimensionsthat the edges of the raised surfaces of one element overlap the edgesof the raised surfaces of a pair of ilow passages on the cooperatingvalve element.

4. A fluid flow control mechanism comprising a stationary cylinder and amovable piston, the piston having a pair of valve elements cooperatingwith the Walls of the cylinder to providea substantially leak-proof t,said elements being-mounted for axial movement on the piston rod andbeing normally spaced apart to form a gap between said pair of elements,saidv elements having flow passages in angularly spaced relation, thepassages of one element being in staggered relation to the passages ofthe other element, the flow passages of said valve elements being shapedto minimize the resistance to the ilow of fluid from between said valveelements upon the closing of the valve elements in response to abnormalexternal force on an outer face of the valve elements.

5. A fluid flow control mechanism comprising a stationary cylinder and amovable piston,

the piston having a pair of valve elements cooperating with the walls ofthe cylinder to provide a substantially leak-proof fit, said elementsbeing mounted for axial movement on the piston rod and being normallyspaced apart to form a gap-between said pair of elements, said elementshaving flow passages in angularly spaced relation, the passages of oneelement being in staggered relation to the passages of the otherelement, the flow passages of said valve elements being flared at theirends in the juxtaposed faces of said valve elements.

6. A fluid flow control device for the steering mechanism of automotivevehicles comprising a cylinder and a movable piston having a pair ofvalve elements disposed in said cylinder and cooperating with the wallthereof, one end of the cylinder being connected by an adjustablebracket to the rigid part of the vehicle and the piston rod beingconnected to the steering mechanism of the vehicle, said piston elementhaving flow passages in staggered relation to control the rate of pistontravel in the fluid of said cylinder, the opposed ow passages on theinner faces of the elements having flared entrant portions.

'1. A uid flow control device for-the steering mechanism of automotivevehicles comprising a cylinder and a movable piston having a pair ofvalve elements disposed in said cylinder and cooperating with the wallthereof, one end of the cylinder being connected by an adjustablebracket -to the rigid part of the vehicleand the piston rod beingconnected to the steering mechanism of the vehicle, said piston elementshaving ow passages in staggered relation to control the rate of pistontravel in the fluid of said cylinder, and

means on the juxtaposed faces of said pair of valve elements tominimizethe resistance to the flow of the fluid from between saidelements when they are moving into contact.

8. A :duid flow control device for the steering mechanism of automotivevehicles comprising a cylinder and a movable` piston having a pair ofvalve elements disposed in said cylinder and cooperating wlth the wallthereof, said elements being normally held apart by resilient meansdisposed about the piston rod, one end of the cylinder being connectedby an adjustable bracket to the rigid part of the vehicle and the pistonrod being connected to the steering mechanism of the vehicle, saidpiston element having flow passages in staggered relation to control therate of piston travel in the fluid of said cylinder, the opposed flowpassages on the inner faces of the elements having ared entrantportions.

9. A fluid now control device for the steering mechanism of automotivevehicles comprising a cylinder and a movable piston having a pair ofmovably mounted valve elements disposed in said cylinder and cooperatingwith the wall thereof,

vsaid elements being provided with opposed aligned recesses concentricwith said piston rod and a spring surrounding the piston rod anddisposed insaid recesses for maintaining the valve elements normallymoved apart on said rod, one end of the cylinder being connected by anadjustable bracket to the rigid part of the vehicle and the piston rodbeing connected to the steering mechanism of the vehicle, said pistonelement having ow passages in staggered relation to control the rate ofpiston travel in the fluid of said cylinder, the opposed flow passageson the inner faces of the elements having flared entrant portions.

10. A uid control device for the steering mechanism of automotivevehicles comprising a cylinder and a movable piston having a pair ofmovable valve elements disposed in said cylinder and cooperating withthe wall thereof, a pair of nuts threaded on the end of said piston rod,hav'- ing cylindrical portions extending inwardly from the heads of thenuts, the heads of the nuts and said cylindrical portions forming aperipheral recess, said valve elements movably disposed in said recessupon said cylindrical portions, said valve elements having opposedrecesses, a spring disposed in said recesses and conned by the wallthereof and the ajacent surfaces of said portions, said spring acting tonormally maintain the valve elements in spaced relation, one end of thecylinder being connected by an adjustable bracket to the rigid part ofthe vehicle and the piston rod being connected to the steering mechanismof the vehicle, said piston element having flow passages in staggeredrelation to control the rate of piston travel in the fluid of saidcylinder, the opposed ilow passages on the inner faces of the elementshaving flared entrant portions.

11. A steering stabilizer comprising a cylinder, a piston rod movabletherein having a piston head including valve means, and a packingthrough which the piston rod reciprocates disposed within the cylinderand forming an end wall of a working chamber therein, said packing yincluding a compressible material and coniining means thereforthrougnwhich the piston rod extends, the` conning means on the chamberside of. the packing being movable when said valve means lock and aremoved in the direction of the packing whereby the compressible materialclaim 11 in which the compressible material is composed of syntheticrubber having incorpo-f rated therein a lubricating material.

14. A steering stabilizer in accordance with claim 11 in which thepackingmaterial is conned .by means adjacent one-end of the cylin-f derand also acted uponat said. end by resilient means. Y

FRANCIS P. MYERS. RAWSON E. STARK.

